package filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

public class HibernateFilter implements Filter {

	private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
	private static org.hibernate.SessionFactory sessionFactory;

	private static Configuration configuration = new Configuration();
	private static ServiceRegistry serviceRegistry;

	@Override
	public void init(FilterConfig arg0) throws ServletException {
		try {
			configuration.configure();
			serviceRegistry = new ServiceRegistryBuilder().applySettings(
					configuration.getProperties()).buildServiceRegistry();
			sessionFactory = configuration.buildSessionFactory(serviceRegistry);
		} catch (Exception e) {
			System.err.println("%%%% Error Creating SessionFactory %%%%");
			e.printStackTrace();
		}
	}

	@Override
	public void doFilter(ServletRequest req, ServletResponse res,
			FilterChain chain) throws IOException, ServletException {

		try {
			System.out.println("hello");
			chain.doFilter(req, res);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			HibernateFilter.closeSession(); // 在过滤器中统一关闭session
		}

	}

	@Override
	public void destroy() {

	}

	public static Session getSession() throws HibernateException {
		Session session = (Session) threadLocal.get();

		if (session == null || !session.isOpen()) {
			if (sessionFactory == null) {
				rebuildSessionFactory();
			}
			session = (sessionFactory != null) ? sessionFactory.openSession()
					: null;
			threadLocal.set(session);
		}

		return session;
	}

	public static void rebuildSessionFactory() {
		try {
			configuration.configure();
			serviceRegistry = new ServiceRegistryBuilder().applySettings(
					configuration.getProperties()).buildServiceRegistry();
			sessionFactory = configuration.buildSessionFactory(serviceRegistry);
		} catch (Exception e) {
			System.err.println("%%%% Error Creating SessionFactory %%%%");
			e.printStackTrace();
		}
	}

	public static void closeSession() throws HibernateException {
		Session session = (Session) threadLocal.get();
		threadLocal.set(null);

		if (session != null) {
			session.close();
		}
	}

}
